Children of the Forest

The Children of the Forest are a legendary people in Westeros. They were said to have been allies of the First Men and had various magical powers such as greensight and green dreams. When the First Men came to Westeros, the two species had a long war, which ended with a peace treaty known as the Pact. To seal the Pact, they carved faces on all the weirwoods on the island in middle of Gods Eye; hence the name Isle of Faces.

The peace between human and the Children of the Forest shattered when a second group of humans, Andals, came to Westeros. While the First Men converted to the Children of Forest's religion, Andals had their own religion, the Seven. Andals slaughtered all the Children of the Forest they found and cut down many weirwoods. Children of the Forest are considered extinct, but myths and legends about them continue to be told in the series, and A Dance with Dragons reveals that a few still survive.

In one of Bran Stark's POV chapters in A Dance with Dragons, it is revealed that the children of the forest still exist. Bran, Hodor, and Meera and Jojen Reed meet a child of the forest beyond the Wall. She is described as smaller than a human child, with dappled skin, wearing a cloak of leaves. Her hair is brown, red, and gold, tangled with flora, and her eyes are "large and liquid, gold and green, slitted like a cat's eyes" (A Dance with Dragons, pg 175). The child of the forest leads Bran's party through an underground cavern, leading them to the fabled three-eyed crow.